The present invention relates generally to fluid and electric connectors and more particularly to quick disconnects for use with a plasma arc apparatus in which both fluid and electric power are conducted through the quick disconnect.
In manually operated plasma arc torches of the known art, a torch is commonly connected to a power supply through a torch lead, which is typically available in a variety of lengths according to requirements of a specific application. Additionally, the torch lead is often secured to the power supply using a quick disconnect such that the torch lead may be quickly and easily removed from the power supply in the event that the torch and/or torch lead is damaged or requires replacement. Further, the quick disconnect allows a torch and torch lead to be interchanged with a variety of power supplies if necessary.
Generally, the torch lead side of the quick disconnect comprises a housing, commonly in the form of a plug, with a variety of electrical and fluid, (e.g., gas, liquid), conductors disposed therein. Similarly, the power supply side of the quick disconnect also comprises a housing, commonly in the form of a socket adapted to receive the plug, with a mating set of electrical and fluid conductors disposed therein. Generally, one or more main power pins and mating sockets conduct both electricity and fluid for operation of the torch, through which high current, high voltage, and/or high frequency electrical power is provided to initiate and operate a plasma arc. Further, a plurality of signal pins and mating signal pin sockets conduct electrical signals for operation of the torch such as a trigger switch or electrical grounding, among others. Moreover, some or all of the conductors, including the main power pins and sockets, may be replaceable such that an inoperative or broken conductor may be replaced in the field as necessary.
Typically, the fluid and electrical conductors disposed within the plug and socket housings form connections when the quick disconnect is fully engaged. In some quick disconnects of the known art, all of the connections are simultaneously broken when the quick disconnect is disengaged. In other known art connectors, a fluid connection is broken first, followed by breaking the signal pin connections and then breaking the main power connection last. Unfortunately, the sequence of breaking connections in quick disconnects of the known art may cause inadvertent arcing if the quick disconnect was disengaged during operation of the torch. Further, gas may leak from the quick disconnect when the quick disconnect is not fully engaged. As a result, the plasma arc torch may become damaged and operate inefficiently when the quick disconnect is not fully engaged.
Accordingly, there remains a need in the art for a quick disconnect that reduces the risk of arcing and that prevents damage to the plasma arc apparatus when a quick disconnect is not fully engaged.
In one preferred form, the present invention provides a quick disconnect for use in a plasma arc apparatus comprising at least one signal connection, a pilot return connection, at least one fluid connection, and a main power connection. Accordingly, the connections are configured within the quick disconnect such that when the quick disconnect is disengaged, the signal connection breaks before the pilot return connection, the fluid connection, and the main power connection. Further, the pilot return connection breaks before the fluid connection and the main power connection, and the fluid connection breaks before the main power connection. Finally, the main power connection breaks after the signal connection, the pilot return connection, and the fluid connection. Generally, the signal connection is shorter that the pilot return connection, the fluid connection, and the main power connection. In addition, the pilot return connection is shorter than the fluid connection and the main power connection, and the fluid connection is shorter than the main power connection. As a result, the connections are broken in a specific order as the quick disconnect is disengaged.
In another preferred form, a quick disconnect for use in a plasma arc apparatus is provided that comprises at least one signal connection, at least one fluid connection, and a main power connection. Accordingly, the connections are configured such that when the quick disconnect is disengaged, the signal connection breaks before the fluid connection and the main power connection, the fluid connection breaks before the main power connection, and the main power connection breaks after the signal connection and the fluid connection. Similarly, the signal connection is shorter than the fluid connection and the main power connection, and the fluid connection is shorter than the main power connection.
In yet another form of the present invention, a method of disengaging a quick disconnect in a plasma arc apparatus is provided that comprises the steps of disengaging the quick disconnect such that at least one signal connection breaks before a pilot return connection, a fluid connection, and a main power connection. The quick disconnect is further disengaged such that the pilot return connection breaks before the fluid connection and the main power connection. Then, the quick disconnect is further disengaged such that the fluid connection breaks before the main power connection, and accordingly, the main power connection breaks after the signal connection, the pilot return connection, and the fluid connection.
As used herein, a plasma arc apparatus shall be construed by those skilled in the art to be an apparatus, whether manual or automated, that generates or uses plasma for cutting, welding, spraying, or marking operations, among others. Accordingly, the specific reference to plasma arc cutting torches or plasma arc torches herein shall not be construed as limiting the scope of the present invention.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.